My Thread Library

My thread is a user level thread library. That is, all the threads in a process are mapped to single kernel thread ( similar to GNU pth library). The key ingredients of this threading library are the functions setjmp and longjmp used to store and restore the contexts of the specific threads.

We mock interrupt based scheduling of the threads. ualarm system call is used to generate SIGALRM signal at regular time intervals playing the role of timer interrupt to indicate that the burst of the thread is over. The signal handler registered for SIGALRM carries out the task of saving the context of the running thread and restoring the context of one of the threads eligible to be run next according to the scheduling policy from the thread queue.

Usage :

Simply include the file mythread.h in your .c file and you are good to go.

Manual :

int create(void ( * f) ( void )) : Creates a new thread with the function pointer passed as argument. Create returns the thread id of the thread.

void start() : This starts the scheduler of the thread library which in turn fetches thread from the queue and starts the execution of the threds.

int createWithArgs( (void * ) ( * f ) ( void * ) ) : This creates a thread which takes a function pointer to function which takes void * as argument and returns void * . Just like pthreads.

Note :

Please note that this is not a full fledged thread library and only a part of a proof-of-concept exercise. Though this library might give a feel of a threading environment, it is not designed to meet the performance requirement of a threading environment. For example, if one of the threads makes a blocking system call, then all the threads are blocked.

Please do not handle the SIGALRM signal in your code as this will lead to malfunctioning of the library.